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Bulletin quotidien sur l'activité solaire et géomagnétique du SIDC

Publié: 2025 Aug 16 1231 UTC

Prévisions SIDC

Éruptions solaires

C-class flares expected, (probability >=50%)

Géomagnétisme

Quiet (A<20 and K<4)

Moniteur de Flux de Proton

Quiet

	Flux de 10 cm	Ap
16 Aug 2025	120	007
17 Aug 2025	120	007
18 Aug 2025	120	013

Régions solaires actives et éruptions solaires

Solar flaring activity was low over the past 24 hours, with only C-class flares identified. A total of 9 numbered sunspot groups were observed on the solar disk. Several of the SIDC Sunspot Groups have Alpha magnetic configurations and did not produce any flaring activity. The most productive region was SIDC Sunspot Group 590 (NOAA Active Region 4172), currently located at N09W78, which has a Beta magnetic configuration and was decreasing over the past 24 hours. This region produced the largest flare, a C7.7 flare (SIDC Flare 5156), peaking on August 15 at 21:22 UTC. Solar flaring activity is expected to remain low over the next 24 hours, with C-class flares very likely.

Éjection de masse coronale

No Earth-directed coronal mass ejections (CMEs) were observed over the past 24 hours. Only a very small number of minor CMEs were detected, none of which are expected to impact Earth. Moreover there are few large filaments visible on the disc, however they appear the remain stable.

Trous coronaux

The recurring SIDC Coronal Hole 104 (polar-south, positive polarity) reached the central meridian on August 14. The SIDC Coronal Hole 116, a mid-latitude coronal hole with negative polarity, first reached the central meridian on August 15, continues its transit across the central meridian.

Vent solaire

Solar wind parameters indicate a return to a slow solar wind regime. Solar wind speed varied between 340 and 450 km/s. The total interplanetary magnetic field (Bt) remained around 5 nT, and the southward interplanetary magnetic field (Bz) component fluctuated between -4.0 nT and 3.6 nT. The high-speed streams associated with SIDC Coronal Hole 116, a mid-latitude coronal hole with negative polarity now facing Earth, are forecast to influence solar wind conditions on August 18-19.

Géomagnétisme

Geomagnetic activity was quiet over the past 24 hours, with NOAA Kp indices between 1 and 2, and the Belgian K-index also between 1 and 2. In response to the expected arrival of high-speed streams associated with SIDC Coronal Hole 116, minor geomagnetic disturbances or active conditions are possible on August 18-19.

Niveaux de flux de protons

Proton flux remained below 10 pfu over the past 24 hours. A slight enhancement cannot be fully excluded due to the number of sunspot groups on the solar disk but is considered unlikely.

Flux d'électrons sur l'orbite géostationnaire

The greater than 2 MeV electron flux measured by GOES 18 and GOES 19 remains above the 1000 pfu threshold in response to high-speed streams associated with SIDC Coronal Hole 123 observed over the past days. Electron flux levels are expected to fluctuate around the 1000 pfu threshold over the next 24 hours. The 24-hour electron fluence remains at moderate levels and is expected to return to normal levels over the next 24 hours.

Estimation du nombre international de taches solaires (ISN) pour aujourd'hui : 129, sur la base de 08 stations.

Indices solaires pour 15 Aug 2025

Nombre de Wolf, observé par Catania	///
Flux solaire à 10 cm	123
AK Chambon La Forêt	012
AK Wingst	010
Ap estimé	010
Nombre international de taches solaires estimé	144 - Basé sur 25 stations

Résumé des événements marquants

Données fournies par le Solar Influences Data analysis Center© - SIDC - Traité par SpaceWeatherLive

Toutes les heures sont indiquées en UTC

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